The purpose of the Viral Core is to provide a service to the individual projects of the Program Project. It will do so by constructing, amplifying, purifying and quality testing recombinant replication-deficient adenoviruses that will be required to accomplish the specific aims proposed in the individual projects. The Viral Core will make these viruses available to the individual project leaders who have indicated an interest in using the resources of the Core. In addition, the personnel in the Core will make available their expertise in the use of these viruses and in solving potential problems associated with their use. Recombinant adenoviruses offer an extremely efficient means of introducing and expressing exogenous genes in mammalian cells. They are particularly useful in experiments using primary cells such as human aortic or umbilican vein endothelial cells, in which standard transfection modalities such as calcium phosphate, electroporation and lipofectamine achieve very low transfection efficiencies and levels of transgene expression. Recombinant adenoviruses have the advantage of achieving transfection efficiencies approaching 100% in most mammalian cells in vitro, combined with the very high levels of transgene expression. These properties then obviate the need for selecting successfully transfected cells and permit the performance of direct biochemical and molecular assays on entire cell populations. In addition to being used for cells in culture, the recombinant adenoviruses constructed by the Viral Core will also be used in preliminary experiments involving ex vivo models of cardiac ischemia-reperfusion injury. Although transfection efficiencies are lower in vivo or ex vivo than in vitro, recent evidence suggests that adenoviruses in conjunction with other manipulations are useful for gene transfer in such models. Thus the adenovirus vectors developed by the Viral Core, may in the future, have utility in clinical gene therapy trials aimed at preventing cardiac ischemia-reperfusion injury.